Candidiasis (moniliasis) is skin infection with
Candida sp, most commonly
Candida albicans. Infections can occur anywhere and are most common in skinfolds, digital web spaces, genitals, cuticles, and oral mucosa. Symptoms and signs vary by site. Diagnosis is by clinical appearance and potassium hydroxide wet mount of skin scrapings. Treatment is with drying agents and antifungals.

Most candidal infections are of the skin and mucous membranes, but invasive candidiasis is common among immunosuppressed patients and can be life threatening. Systemic candidiasis is discussed in Fungi. Vulvovaginal candidiasis is discussed in Candidal Vaginitis.

Etiology

Candida is a group of about 150 yeast species.
C. albicans is responsible for about 70 to 80% of all candidal infections. Other significant species include
C. glabrata,C. tropicalis,C. krusei, and
C. dubliniensis.

Candida is a ubiquitous yeast that resides harmlessly on skin and mucous membranes until dampness, heat, and impaired local and systemic defenses provide a fertile environment for it to grow.

Risk factors for candidiasis include

Hot weather

Restrictive clothing

Poor hygiene

Infrequent diaper or undergarment changes in children and elderly patients

Candidiasis occurs most commonly in intertriginous areas such as the axillae, groin, and gluteal folds (eg, diaper rash), in digital web spaces, on the glans penis, and beneath the breasts. Vulvovaginal candidiasis is common among women. Candidal nail infections and paronychia may develop after improperly done manicures and in kitchen workers and others whose hands are continually exposed to water (see Onychomycosis ). In obese people, candidal infections may occur beneath the pannus (abdominal fold). Oropharyngeal candidiasis is a common sign of local or systemic immunosuppression.

Candidal infection is a frequent cause of chronic paronychia, which manifests as painful red periungual swelling. Subungual infections are characterized by distal separation of one or several fingernails ( onycholysis), with white or yellow discoloration of the subungual area.

Perlèche is candidiasis at the corners of the mouth, which causes cracks and tiny fissures. It may stem from chronic lip licking, thumb sucking, ill-fitting dentures, or other conditions that make the corners of the mouth moist enough that yeast can grow.

Chronic mucocutaneous candidiasis is characterized by red, pustular, crusted, and thickened plaques resembling psoriasis, especially on the nose and forehead, and is invariably associated with chronic oral candidiasis.

Diagnosis

Clinical appearance

Potassium hydroxide wet mounts

Diagnosis of mucocutaneous candidiasis is based on clinical appearance and identification of yeast and pseudohyphae in potassium hydroxide wet mounts of scrapings from a lesion. Positive culture alone is usually meaningless because
Candida is omnipresent.

Treatment

Sometimes drying agents

Topical or oral antifungals

Intertriginous infection is treated with drying agents as needed (eg, Burow solution compresses applied for 15 to 20 min for oozing lesions) and topical antifungals (see Table: Options for Treatment of Superficial Fungal Infections*). Powdered formulations are also helpful (eg, miconazole powder bid for 2 to 3 wk). Fluconazole 150 mg po once/wk for 2 to 4 wk can be used for extensive intertriginous candidiasis; topical antifungal agents may be used at the same time.

*Advantages of one topical drug over another for most infections are not clear. For skin infections, allylamines have good activity against dermatophytes but weaker activity against
Candida; imidazoles have better activity against both dermatophytes and
Candida. Adverse effects are rare, but all topical antifungals can cause skin irritation, burning, and contact dermatitis. Drug doses may vary by indication.

Oral antifungals can cause hepatitis and neutropenia. Periodic laboratory monitoring of hepatic function and of CBC is recommended when oral antifungals (eg, itraconazole, terbinafine) are given for > 1 mo.

Oral itraconazole, terbinafine, and fluconazole are metabolized through the cytochrome P-450 enzyme system and thus have many potential drug interactions. Some interactions may be severe; cardiac arrhythmias are a risk for some people. Care should be taken to minimize the effects of interactions with these drugs.

Candidal diaper rash is treated with more frequent changes of diapers, use of super- or ultra-absorbent disposable diapers, and an imidazole cream bid. Oral nystatin is an option for infants with coexisting oropharyngeal candidiasis; 1 mL of suspension (100,000 units/mL) is placed in each buccal pouch qid.

Candidal paronychia is treated by protecting the area from wetness and giving topical or oral antifungals. These infections are often resistant to treatment. Thymol 4% in alcohol applied to the affected area twice daily is often helpful.

Oral candidiasis can be treated by dissolving 1 clotrimazole 10-mg troche in the mouth 4 to 5 times/day for 14 days. Another option is nystatin oral suspension (4 to 6 mL of a 100,000 unit/mL solution) held in the mouth for as long as possible and then swallowed or expectorated 3 to 4 times/day, continuing for 7 to 14 days after symptoms and signs have resolved. A systemic antifungal may also be used (eg, fluconazole 200 mg po on the first day, then 100 mg po once/day for 2 to 3 wk thereafter).

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